Field of the Invention
The invention relates to a device for reducing noise emissions of a machine for printing flat materials, particularly a rotary printing machine wherein the flat materials are transportable over an impression cylinder.
Printing machines of this type, particularly offset printing machines, generate noise in the region of the impression cylinder in printing the flat material and emit this noise into the environment. In this regard, so-called paper-tearing noise is involved, a noise which arises in the printing of paper sheets which are used as flat printing material when they are through-transported between an impression cylinder and an ink applicator element, namely a rubber blanket cylinder, and when they disengage from the ink depositing element. It is possible to reduce noise by primary measures only to a limited extent. But because excessive noise emission from the printing machine is uncomfortable or even hazardous to the operating personnel, the dispersal of airborne noise must be minimized by secondary noise insulation measures. Muffling, on one hand, and damping, on the other hand, are secondary sound insulation measures that come into consideration. Muffling is the conversion of sound energy into heat; it is accomplished by using fibrous or porous absorption materials. Damping is the blocking of sound dispersal; for airborne noise it is preferably achieved by using baffles. Heretofore, the noise arising during the printing of flat material has not been purposefully counteracted as such, but rather only in the context of general sound insulation measures affecting the overall printing unit.
In the German Published Non-prosecuted Patent Application (DE-OS) 34 23 272 A1, a sheet offset printing machine is disclosed including a conveyor mechanism for paper sheets in the form of a chain conveyor having noise emissions which are reduced by using a muffler and a partial encapsulation at the top and bottom sides. The printing machine comprises printing units that have pivoting protective plastic hoods. The protective hoods form an outer cover for the respective printing unit and make it possible to access the elements of the unit easily by swinging the hoods away. In addition, other units of the printing machine such as the drive, delivery and feeder, and the footstep are encapsulated and are constructed damped and, if necessary or desirable, muffled using sound insulation elements. Besides hoods, plates (preferably perforated) which are connected to elements which are formed of muffling material are also provided as sound insulation elements. Fiberglass and foam are suggested muffling materials. What is known as anti-drone material is applied to the walls of the printing machine to attenuate structure-borne noise.
The German Utility Model (DE-GM) 7 325 088 discloses a buckle folding device having a folding unit wherein paper sheets are processed. The paper sheets slide with the aid of transport cylinders along sheet guide rails which are disposed in so-called buckle plates or folding pockets. The buckle plates are surrounded by a swinging multipartite sound insulation mechanism that virtually encapsulates the folding unit. The sound insulation mechanism is formed of steel panel walls which are covered on the exterior side by an open-pored muffling material. In turn, the muffling material is sealed on the interior side by a dustproof foil.
It is accordingly an object of the invention to provide, by a simple and most economical construction, an optimally effective reduction of the noise emissions arising at the impression cylinder during printing of the flat material.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a device for reducing the noise emissions of a machine for printing flat material, wherein flat material is transportable across an impression cylinder, comprising at least one muffling element disposed across a portion of a transport path of the flat material extending along the impression cylinder, directly behind or downline from a nip, as viewed in the direction of the transport path, and at a spaced distance from the impression cylinder.
In accordance with another feature of the invention, the muffling element serves for shielding the nip on at least one side of the transport path of the flat material.
In accordance with a further feature of the invention, the muffling element is affixed to a bearing element.
In accordance with an added feature of the invention, the bearing element is movably mounted.
In accordance with an additional feature of the invention, the bearing element has a hollow interior wherein the muffling element is disposed.
In accordance with yet another feature of the invention, the bearing element is rigid with a footstep for accessing the machine.
In accordance with yet a further feature of the invention, the footstep is pivotably mounted.
In accordance with yet an added feature of the invention, the bearing element comprises a baffling arrangement which is connected to the muffling element.
In accordance with yet an additional feature of the invention, the bearing element is constructed as a baffling arrangement connected to the muffling element.
In accordance with still another feature of the invention, the bearing element is constructed at least partly as a muffling element.
In accordance with still a further feature of the invention, the bearing element comprises a guide element for the flat material, and a muffling element is arranged on a side of the guide element facing away from the impression cylinder.
In accordance with still an added feature of the invention, the bearing element is formed by a perforated plate at least approximately following the curvature of the surface of a jacket of the impression cylinder.
In accordance with still an additional feature of the invention, the device comprises a lateral part for covering an interspace between the muffling element and the impression cylinder at least on one side of the transport path of the flat material.
In accordance with another feature of the invention, the bearing element comprises a lateral part for shielding the impression cylinder at least at one end face thereof.
In accordance with a further feature of the invention, the bearing element comprises a lateral part for shielding a nip on at least one side of the transport path of the flat material.
In accordance with an added feature of the invention, the muffling element is disposed at the lateral part.
In accordance with another aspect of the invention, there is provided a machine for printing flat material, wherein flat material is transportable across an impression cylinder, including a device for reducing the noise emissions of the machine, comprising at least one muffling element disposed across a portion of a transport path of the flat material extending along the impression cylinder, directly behind or downline from a nip, as viewed in the direction of the transport path, and at a spaced distance from the impression cylinder.
In accordance with a concomitant feature of the invention, the machine for printing flat material is an offset printing machine.
The object of the invention is achieved by providing a device for reducing noise emissions wherein at least one muffling element is disposed across a portion of the transport path of the flat material, which extends along the impression cylinder, directly behind a nip and spaced a distance from the impression cylinder.
The portion of the transport path of the flat material which is provided with a sound insulation element is situated directly behind the nip (as viewed in the transport direction) between the impression cylinder and an ink applicator or depositing element, the flat material being transportable through the nip. A portion of the transport path of the flat material extending along the impression cylinder is shielded by at least one muffling element that is disposed at a slight distance from the impression cylinder. The muffling element is preferably arranged so that the flat material that is guided across the impression cylinder can be transportedxe2x80x94through between the muffling element and the impression cylinder, and at the same time the noise that is generated and emitted during the printing of the flat material can immediately be dissipated to a considerable extent in the muffling element that is disposed adjacent the impression cylinder. Specifically, this prevents the generated airborne noise from reaching other components and from propagating. Such a muffling element expediently extends at least over the entire width of the flat printing material and over an appreciable distance along the transport path of the flat material. In this way, it is possible to achieve a particularly effective attenuation of the noise that is generated in the printing of the flat material, because the muffling element is disposed directly behind the nip, i.e., the locus of the noise generation.
In a development of the invention, the nip is shielded by a muffling element on at least one side of the transport path of the flat material. Preferably, in addition to a first muffling element which covers the entire width of the transport path of the flat material, one or more additional muffling elements extend over the height of the interspace between the first sound insulation element and the impression cylinder along the sides of the transport path of the flat material. The muffling elements can be affixed to the interior surfaces of the sidewalls of the printing machine or to separate bearing elements. A still improved sound insulation can be achieved using lateral muffling elements.
In another development of the invention, a muffling element is affixed to a bearing element that is mounted in a movable manner. The bearing element is preferably connected to or constructed in one piece with the printing machine structure and is sufficiently rigid as to permit the utilization of elastic and less rigid materials for the muffling element. The bearing element and the muffling element can form a multiayered composite that has a sufficient rigidity and good noise insulation characteristics. The muffling element can be affixed to the side of the bearing element that faces the impression cylinder and/or the side of the bearing element that is averted from the cylinder. If the muffling element is disposed on the side facing the impression cylinder, and if in addition the flat material is constructed in the form of individual sheets, the muffling element preferably stands at a sufficient spaced distance from the impression cylinder as to prevent the sheets from contacting the muffling element as they disengage from the impression cylinder.
In another embodiment of the invention, the bearing element surrounds a hollow space wherein a muffling element is disposed. Advantageously, the bearing element is constructed as a hollow or U-shaped plate profile with the muffling element inserted in the hollow interior or cavity thereof.
In a preferred development of the invention, the bearing element is constructed in one piece with or is connected to a footstep (specifically a pivoting footstep) for accessing the printing machine. The muffling element can thus be integrated into the existing structure of the printing machine particularly well. A particularly advantageous mechanism for fastening the muffling element is produced when the muffling element, together with the footstep and the bearing element, is arranged in a swinging manner, because the impression cylinder can be accessed rather easily by the operating personnel by swinging the muffling element out or away.
According to another development of the invention, the bearing element comprises or is constructed as a baffling arrangement that is connected to the muffling element. A perforated plate or some other partly sound-permeable structure is provided as the baffling arrangement. Either the whole bearing element or part thereof can be constructed as a baffling arrangement, and either the whole baffling arrangement or parts thereof can be connected to a muffling element. The muffling element can be affixed to the side of the baffling arrangement that faces the impression cylinder and/or to the side that is averted from the impression cylinder.
The bearing element is preferably constructed at least in part as a muffling element. The bearing element thus takes over all or part of the muffling and sound-damping tasks. In this embodiment, the bearing element is advantageously constructed as a microporous rigid structure with a high stability. The bearing element may, but need not, be provided with an additional muffling element.
In another embodiment of the invention, the bearing element has a guide element for the flat material, at which a muffling element is arranged on the side that is averted from the impression cylinder. The guide element serves to guide the flat material, namely the individual sheets, and expediently forms a baffling arrangement that is semi-permeable to sound, and forms a sound insulation device together with the muffling element.
A preferred development of the invention provides that the bearing element be formed by a perforated plate which at least approximately follows the curvature of the surface of the jacket of the impression cylinder. A plate which is constructed in this way can be applied closely to the impression cylinder, so that it can effectively prevent individual sheets of the flat material from disengaging too far. Using a perforated plate, it is possible to realize a baffling arrangement that is particularly easy to produce and that can simultaneously serve as a sheet guiding element. In this case, a muffling element can be attached in a protected manner to the side of the plate that is averted form the impression cylinder. The plate and the muffling element thus together form an effective sound insulation device.
In another development of the invention, the bearing element comprises a parallel arrangement of sheet guide rails which at least approximately follow the curvature of the jacket of the impression cylinder. Such sheet guide rails are particularly easy to produce. They can effectively prevent individual sheets of the flat material from disengaging too far from the impression cylinder. In addition, because of the baffling properties thereof, they also serve as a baffling arrangement, and because of the rigidity thereof, as a bearing element for a muffling element that is arranged thereon on the side that is averted from the impression cylinder.
The bearing element preferably comprises a lateral part that covers the interspace between the muffling element and the impression cylinder to the side of the transport path of the flat material. A lateral part is preferably arranged on each side of the transport path of the flat material. The lateral parts are disposed between the muffling element and the jacket of the impression cylinder and form components of a baffling arrangement that shields the transport path of the flat material both above and at the side.
In another development of the invention, the bearing element comprises a lateral part that shields the impression cylinder at an end face thereof. Preferably, a lateral part is disposed on each side of the transport path of the flat material. The lateral parts surround the impression cylinder at the end faces thereof as well and effectuate a particularly effective baffling.
The bearing element preferably comprises a lateral part that shields the nip on one side of the transport path of the flat material. A lateral part is expediently disposed on each side of the nip. The lateral parts surround the impression cylinder as well as the ink applicator or depositing element, which is preferably constructed as a rubber blanket, in the region of the nip, thereby effectuating a particularly effective baffling.
In a further development of the invention, a muffling element is disposed at the lateral part. The muffling element can be disposed at the interior surface of the lateral part, which faces the impression cylinder, or at the exterior surface thereof, which is averted from the impression cylinder.
The subject matter of the invention also comprises a machine for printing flat material, particularly an offset printing machine, in which the device for reducing noise emissions in accordance with the invention is provided.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a device for reducing noise emissions, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: